Is cos^2(x)(tan^2(x)+1)=1 ?

The answer to whether cos^2(x)(tan^2(x)+1)=1 is True

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prove cos^2(x)(tan^2(x)+1)=1

prove

cos^{2} (x) (tan^{2} (x) + 1) = 1

True

Solution steps

cos^{2} (x) (tan^{2} (x) + 1) = 1

Manipulating left side

cos^{2} (x) (tan^{2} (x) + 1)

Express with sin, cos

(1 + tan^{2} (x)) cos^{2} (x)

Use the basic trigonometric identity:

tan (x) = \frac{sin ( x )}{cos ( x )}

= (1 + (\frac{sin ( x )}{cos ( x )})^{2}) cos^{2} (x)

Simplify

(1 + (\frac{sin ( x )}{cos ( x )})^{2}) cos^{2} (x) : cos^{2} (x) + sin^{2} (x)

(1 + (\frac{sin ( x )}{cos ( x )})^{2}) cos^{2} (x)

Apply exponent rule:

(\frac{a}{b})^{c} = \frac{a ^{c}}{b ^{c}}

= cos^{2} (x) (\frac{sin ^{2} ( x )}{cos ^{2} ( x )} + 1)

Join

1 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )} : \frac{cos ^{2} ( x ) + sin ^{2} ( x )}{cos ^{2} ( x )}

1 + \frac{sin ^{2} ( x )}{cos ^{2} ( x )}

Convert element to fraction:

1 = \frac{1 cos ^{2} ( x )}{cos ^{2} ( x )}

= \frac{1 \cdot cos ^{2} ( x )}{cos ^{2} ( x )} + \frac{sin ^{2} ( x )}{cos ^{2} ( x )}

Since the denominators are equal, combine the fractions:

\frac{a}{c} \pm \frac{b}{c} = \frac{a \pm b}{c}

= \frac{1 \cdot cos ^{2} ( x ) + sin ^{2} ( x )}{cos ^{2} ( x )}

Multiply:

1 \cdot cos^{2} (x) = cos^{2} (x)

= \frac{cos ^{2} ( x ) + sin ^{2} ( x )}{cos ^{2} ( x )}

= \frac{cos ^{2} ( x ) + sin ^{2} ( x )}{cos ^{2} ( x )} cos^{2} (x)

Multiply fractions:

a \cdot \frac{b}{c} = \frac{a \cdot b}{c}

= \frac{( cos ^{2} ( x ) + sin ^{2} ( x ) ) cos ^{2} ( x )}{cos ^{2} ( x )}

Cancel the common factor:

cos^{2} (x)

= cos^{2} (x) + sin^{2} (x)

= cos^{2} (x) + sin^{2} (x)

= cos^{2} (x) + sin^{2} (x)

Rewrite using trig identities

cos^{2} (x) + sin^{2} (x)

Use the Pythagorean identity:

cos^{2} (x) + sin^{2} (x) = 1

= 1

= 1

We showed that the two sides could take the same form

\Rightarrow True

cos (x) = \frac{1}{sec ( x )}

1 - cos^{2} (θ) = sin (θ) cos (θ) tan (θ)

arctan (x) = \frac{1}{tan ( x )}

tan (\frac{θ}{2}) = csc (θ) - cot (θ)

cos (4 x) = 1 - 8 sin^{2} (x) + 8 sin^{4} (x)

Is cos^2(x)(tan^2(x)+1)=1 ?
The answer to whether cos^2(x)(tan^2(x)+1)=1 is True